In the last twelve years, controlled studies have described desensitization based on the oral administration of allergens (1). This method is based on the fact that the oral administration of an antigen facilitates the acquisition of an immunological tolerance to it. The digestive route constitutes the mode of contact of the body with antigens, of food or microbial origin. However, allergic reactions are rare. Oral administration of sheep red blood cells (SRBC) to rats prevents the rats from later producing anti-SRBC antibodies after a subcutaneous injection, whereas, without the prior oral intake, the allergic response would have been present. This phenomenon constitutes what is referred to immunologically as oral tolerance.
This oral desensitization method has been validated in prospective and controlled studies, and makes it possible to reduce the risks of anaphylaxis, in particular for birch pollen and acari. It is already available on the vaccines market in a presentation in drinkable form (sold by the company Laboratoire des Stallergenes--Paris).
Moreover, it may be considered that the benefit, in terms of protecting infants against allergy to milk, which has been observed since the introduction of new, enzymatically predigested powdered milk formulations, would result from the induction of immunological tolerances by the presentation of antigens in the form of peptides.
However, it is difficult to predict or state the efficacy of the desensitization. Clinical observation makes it possible, after the event, to confirm or deny any improvement in the symptoms.
It is known, from international patent application WO 96/36880, to be able to detect and/or quantify ligands specific to a pathology associated with an allergic or autoimmune response or lung cancer, by means of a test of competition between ligands present in a sample and other discriminable ligands. This test is based on the fact that allergic and symptomatic individuals recognize, by means of their antibodies, epitopes different from those recognized by the antibodies of tolerant individuals on the same specific antigenic structure of said pathology. That document also describes the possibility of measuring the evolution of this specificity, in particular in the case of children who are allergic to milk and the change toward the in vivo acquisition of tolerance to milk.